These Darkened Wings
by CastielsDemon
Summary: Castiel feels a demonic evil inside of him after an attack from a demon. He has been contaminated with demonic power - will Dean and Sam be able to save him before Cas goes darkside, or will Cas finally succumb to obeying Lucifer?
1. Chapter 1

Summary: Castiel feels a demonic evil inside of his veins after a demon bites him in a battle. He has been contaminated with the demon power, and it is only a matter of time before he turns 100% dark side. Will Dean and Sam be able to save him from his sadistic destiny, or will Castiel end up obeying Lucifer?

'Rob, Scott...this…is where we strike'

A leading demon named Blake, male; middle aged; balding blonde hair and brown eyes, pointed towards a map that lay across an oak table. Both Rob and Scott, who were lower-class demons stood around him, their hands folded across their chests, their eyes gazing towards the paper location in front of them, as they were central in an abandoned warehouse.

Creasing their eyebrows towards each other, Rob and Scott began to speak:

'That's fucking far…'

'Yeah shit man, you could of chose a better spot!'

The leader looked towards them in outrage: 'Silence! You will obey my orders…get your shit together and let's go…'

Sighing, the two other demons began to pick up their belongings that were scattered around them, as Blake began to roll up the map, placing it in a duffel bag that was by his feet. As they began to make their way out of the warehouse, the exit door suddenly imploded, the doors swinging on their hinges with such ferocity that a cloud of dust spread out throughout the interior of the building.

'Howdy…' A male Texan accent spoke proudly, his muscular figure suddenly coming into frame as the dust seemed to disperse out into the atmosphere. All three demons stood in shock of the new arrivals – three males; Dean who was holding a shotgun, Castiel who again was wearing his creamy coloured trenchcoat, and Sam, who Blake thought had a terrible haircut – incredibly messy like an unclean, shaggy dog. This thought was quickly forgotten as suddenly Dean raised the shotgun up to his chest, firing it quickly, the recoil digging into his shoulder. The bullet entered Blake's heart, penetrating the arteries as blood spattered over his blackened shirt, killing his soul and his vessel instantly. As he slumped onto the floor in a heap, both Rob and Scott began to charge towards the three intruders.

'I'll fucking kill you!' Rob screamed, beginning to take a knife out of the back of his jeans. Castiel simply regarded him briefly before raising his hand, the angelic power causing Rob to fling back against the table, his back crashing into the wooden fibres as his body landed on the floor in a state of semi-unconsciousness. Scott did not even flinch as he rushed towards Sam, knocking him down instantaneously with an outstretched punch to the temple. Dean began to raise the shotgun again, the butt of the gun rested deeply into his collar bone as suddenly it was snatched from his hands by Scott who threw it on the floor right next to Rob. Rob did not stir as the gun slightly touched his leg, instead his legs and arms stayed twisted underneath the table, as his eyes were closed tight, and his mouth parted in a now lifeless sleep.

'Shit…' Dean cursed under his breath, before he felt the demon place his hands on his chest, pushing him towards the other side of the warehouse, his back landing on the floor harshly as his head flicked back on the floor, the force of the blow causing Dean's vision to blur quickly. Castiel, who became distracted at looking over towards Dean, his face a picture of upmost concern, didn't have time to react as Scott pushed him onto the floor. The lights that hung over the ceiling of the warehouse began to flicker, causing Castiel's wings to shine onto the bitter cold warehouse ground.

Scott scoffed as he noticed the shadows of the wings extending from Castiel's back: 'Heh…don't fucking move angel…'

Castiel struggled underneath the immense weight of the demon whose legs had pinned the angel's arms to the floor, his whole body unable to move, his hands unable to unleash any form of power – he was completely defenceless. Scott began to lick his lips as suddenly he crashed into Castiel's neck, his jagged teeth bore down onto his divine flesh, as blood began to seep into the demon's mouth. Scott sucked harshly, coaxing every last drop of angelic blood out as Castiel continued to thrash under the demon's weight. It was no use, as Castiel's veins began to run cold and his mind started to black out under the effect of his soul losing all of his energy, and of his vessel losing every ounce of life fluid that was needed for him to survive.

'Cas!' Coming too, Sam struggled to stand up as he spotted the gun just metres away from him. Wavering as he lunged towards it, Sam picked up the shotgun in his hands, gripping it tightly as he tried to aim it towards the demon. His vision was clouded as he tried to wake up from his previous unconsciousness, looking towards what looked like himself feasting on an unsuspecting demon. Sam gritted his teeth in anger as he lined up his shot, the aim of the shotgun becoming in sight of Scott's forehead. Sam did not hesitate as suddenly a deafening blast radiated from the gun, and a bullet had exited Scott's head, blood spilling out over Castiel's face like a crimson waterfall. As Scott's body fell next to the broken angel, Sam rushed towards Castiel, who was grunting in agony.

Dean's voice was suddenly heard as he began to rise up, one of his hands holding the base of his head as he gazed towards his brother and his friend: 'Fuck…Cas!'

Sliding down towards the angel, Dean saw the incredible damage on Castiel's neck, looking towards Sam briefly to see if he was the cause. Seeing no blood around his brother's mouth, instead on that of Scott's vessel, he pressed a hand against the wound, which now oozed a stream of thick, maroon liquid, seeping into the collar of Castiel's coat.

Raising one of his hands slowly and gently, Castiel placed it over Dean's, his lips cracked and his eyes closed as he began to whisper: 'I don't feel right Dean…I…I feel different…' Sucking in the air around him, Castiel cried out in pain as the wound on his neck began to pump excruciating sensations into his veins. 'Dean…help me…please…'

Dean gazed over towards Sam who looked at the angel in complete anxiety, his ocean coloured eyes gazed over with a film of fresh tears: 'Sam…what the hell has happened to him?'

Dean grabbed hold of one of Castiel's shoulders, giving them a slow squeeze of comfort as Castiel slowly slipped into unconsciousness.

'…what in God's name has happened to him?'


	2. Chapter 2

The hotel room held an atmosphere of deathly silence as both Sam and Dean stood over Castiel, who was unconscious on the hard, moth-eaten bed. Over the course of six hours, the angel had turned ghastly white and his nails had become brittle and blackened as if a heavy force had crushed each of his saintly fingers. His hair had started to moult, the brown fibres scattered across the pillow as his skin had become taut across his bones, making both his knuckles and his cheekbones stick out unhealthily almost like an omen of death. Every time his auburn eyes glanced over Castiel, Dean grimaced, hating the way his best friend had turned from an immortal being, into something that looked sick and close to dying. It had only been six hours since the attack and Dean hadn't said a single word, not even to Sam's constant requests for something to eat. He had simply stood by the side of Castiel's bed in a trance, the role reversal of the guardian angel evident as Dean maintained the feeling of protection over the fallen angel. Sam could only do the same, yet thoughts raced throughout his mind as to what was happening to Castiel, _he said that he had felt different_, he didn't think that angels had feelings, or even felt pain for that matter? That's what worried Sam the most…as to whether Castiel was to become a threat for both himself and his older brother, and what would he do about it if such a thing happened.

'Sam…' Dean said suddenly, breaking the ominous silence. Sam turned and looked at him in worry: 'Yeah Dean?'

'I need some air…'

Without giving his brother time to respond, Dean snatched his jacket from the floor in which he had viciously thrown it some time ago, and exited the hotel room. Sam could only hear the sound of the Impala's engine firing up, the tyres screeching on the asphalt as his brother drove away to a destination unknown. Sam sighed, bringing a chair that stood behind him closer to the bed, allowing his tired aching body to sit down. Gazing upon the sleeping form in front of him, Sam's eyes noticed an undeniable change happening to Castiel. Even though Sam was fully detoxified from the demon blood and almost of the demon power, he could still see the real face's of demons, not from their vessels, but their internal souls…their charred, corrupted souls that held an everlasting urge for pain and chaos. And here was Castiel's – his soul slowly becoming coal black, and his once feathery white wings becoming harsh and darkening in their now sadistic colour. He was slowly becoming a demon.

'Damn it Cas…' Sam raised one hand to his head, his thumbs rubbing his now closed eyes in annoyance as he struggled to maintain a non-hunter-esque thought for Castiel, resisting the urge to grab his gun and shot the angel/demon point-blank. He had been trained to spot the emerging signs of evil…and to destroy it…why was now any different?

Sam moved from the chair instantly towards the bathroom, his face scowling at the thought. As he approached the sink, he smacked the cold tap on, allowing the water to splash over his hands before throwing the frozen water onto his face. Opening his eyes, he saw they were bloodshot, and his face was pale with anxiety as small droplets of water trickled down his skin. Sam coughed, almost trying to suppress tears as memories of himself turning into a monster invaded his brain, the way he treated his brother, the way he treated everyone…bringing upon the apocalypse…the worst times of his life. Drying his face with his sleeve, Sam proceeded to walk out of the bathroom, almost taking aback as he saw Castiel sitting on the side of the bed, his trenchcoat scrunched up underneath his legs.

'Cas?' Sam walked over towards the angel, but was stopped by Castiel's sudden gaze towards him – his eyes seeming completely black due to the lack of moonlight.

'Don't move Sam…please.' Castiel's voice seemed deeper than usual, almost unrecognisable as he held a hand out towards Sam, an indication to not come any closer.

'Okay Castiel…whatever you want. Are you feeling okay?'

Castiel's head dropped suddenly. 'I don't know how I'm feeling…'

'Well…' Sam tried to make his voice sound calm, although nerves were beginning to creep up through his vocal cords. 'Why don't you try and tell me? And then, maybe…I can help you…'

Suddenly Castiel screamed, his hands clawing at the bed-sheets as he sprang up from his seated position. He turned towards Sam, his posture completely threatening towards the younger Winchester: 'You?! You can't help me!'

Castiel began to hold his head, his teeth gritting in pain as he flung onto the floor. He thrashed violently, Sam's mouth open in shock as he witnessed Castiel's behaviour.

'Cas…Castiel…' Sam sunk down to the same level as Castiel, his hands resting on Castiel's shoulders tightly as he tried to pull the transforming angel up. 'Castiel! Listen to me, you have to get up.' Sam, using one of his arms as leverage, pushed Castiel onto his side, lifting him up as he himself rose up to a standing position. Holding Castiel in both hands, Sam tried to look into Castiel's eyes, trying to make him stand up straight, as he saw Castiel's soul completely turn black like the darkest pits of Hell. Sam tried to disregard this, as he placed his hands onto Castiel's face, trying to make Castiel look at him.

'Castiel, please open you eyes for me…'

As if in excruciating pain, Castiel began to prise open his eyelids, droplets of tears falling down his face as he squinted trying to get them completely open. Castiel felt like he was staring straight up at the sun, as his vision took in the surroundings around him, a filter of burnt redness cascading down over his eyesight, making everything absolutely unbearable to look at.

'Sam…' Castiel's hand suddenly gripped hold of Sam's arm, a certain cry for help. Sam noticed how Castiel's bruised nails had become longer and sharper, a weapon that could be used in attack. 'I can't do it…it hurts…god…it hurts!'

'You have to try…please Cas…'

Castiel obeyed. Even though it hurt him to the core, he opened his eyes wide, allowing Sam to see the full damage of the demon attack. His eyes were now longer cobalt blue…angelic and pure like an ocean wave…instead they were jet black, hard and solid.

Sam could only gasp as suddenly congealed streams of blood began to trickle from Castiel's eyes, and onto his trenchcoat, allowing the material to soak in the demonic fluid. The blood also began to escape from Castiel's nostrils and mouth, his face holding mini-waterfalls of thick, sticky life-fluid, which to Sam's own nose smelt strongly of rotten flesh.

'Sam! Please…help me!'

Sam knew…the transformation was complete.


	3. Chapter 3

Dean wanted to turn back – to return back to the hotel, wrap Castiel up in his arms, comfort him, save him, and promise him a lifetime of immortality, away from all the demons and shit they had faced in the past couple of years. For the first time, he had a true friend, and he wanted to do everything he could to save it. But for some reason, a feeling in the pit of his stomach told him to keep on driving, to grip the harsh texture of the steering wheel with all his might and to never look back. As he stared out of the windshield that protected him from the bitter coldness, Dean suppressed the urge to reverse; instead he focused his attention onto a single diner that stood alone on the side of the highway. He was hungry after all, and surely a double cheeseburger with all the trimmings would reject any thoughts of turning back to the hotel…

XxX

Sam was standing by the hotel window, looking out towards the unknown darkness wondering when his brother was going to return. He had called his cell a few times but to no answer. Castiel sat behind him, tied up under his own orders on the only chair, his skin itching under the harsh rope. His trenchcoat had been removed as had his shoes and socks, which were now lying discarded on the bed. Castiel's wrists were bound to the arms of the chair, whilst his legs were wrapped up together, allowing him almost no movement.

'Sam, help me…' Castiel whispered his voice hoarse in the now broken silence. Sam didn't respond, instead he continued to gaze out of the window, his hands subconsciously rubbing together in anxiety. 'Sam?...' Castiel repeated, confused at the Winchester's ignorance towards him. Sam could only sigh as he turned towards Castiel giving him no response as he walked over towards his laptop. Picking it up from the table, he threw himself down on the bed, the springs squeaking under his weight, as he kicked Castiel's clothes onto the floor, before turning the laptop on. As the laptop sprung into life, the light from the monitor provided almost a warm comfort for Sam as it blinded his surrounding vision, allowing him to become completely immersed in his plans for research.

'Sam.' Castiel's tone was harsher now, almost commanding as Sam continued to block Castiel from any form of communication. It had to be done…if Sam muttered one word to the transformed angel, then he knew he would be in trouble. Something would happen whether it would be a persuasive tone from Castiel to remove him from his bonds, or to provide him with some form of weaponry in case the angels appeared to destroy his vessel. Either way, it would make Sam entirely vulnerable…after all; it was a demon he was dealing with here.

'SAM!' Castiel suddenly leaped up from the chair, his bonds making it almost impossible for him to stand up, the chair sticking to his back like a bloodthirsty leech as he tried to wriggle himself from the ropes.

'Jesus…you told me to put you in the ropes Cas. Stop squirming!'

Sam exhaled harshly as he scooted from the bed, placing the laptop down on the mattress as he did so. Walking over to the hotel door, his hand reached up for the light-switch, flicking it on almost immediately. As he turned around, he saw why Castiel had been so persistent for help.

'Fuck Cas!' Sam rushed over to Castiel's side, seeing how his skin was burning red hot in intensity, the clothes that were on his body were now torn and burnt, black fibres of the material hitting the floor like volcanic ash. Castiel's eyes were solidly black like coal as his face was streaked once more in congealed blood. Sam noticed how his body was more muscular, his bicep muscles seeming to want to rip from his once-saintly flesh as his hands continued to strain against the rough material of the ropes.

'Castiel, please calm down' Sam placed a hand on Castiel's shoulder, but he instantly recoiled in pain, his teeth gritting together as his palm was singed in first-degree burns.

'Sam…' Castiel was breathless as his charcoal eyes stared towards the younger Winchester. 'Get…out…of the…way…'

Sam could only look in confusion as Castiel continued to look at him in agony, noticing a blue-ish tint beginning to radiate from Castiel's body.

'NOW!' Castiel shouted as his hands gripped tightly to the arms of the chair and as his head threw upwards towards the ceiling. As his demonic eyes gazed towards the heavens, his mouth slightly parted and his body shaking with ferocity, Sam threw himself out of the way, as Castiel suddenly unleashed a sapphire blue energy from his mouth and eyes. The heat from this energy grew hotter as it escaped outwards from Castiel's body, propelling itself away from his flesh and out of the hotel room in an almost savage frenzy. As Sam began to sit upright, his eyes turned towards the angel's shadow on the grey wall made by the new illuminations, and he saw the feathers from Castiel's wings fall apart like brittle autumn leaves onto the floor, completely invisible to the human eye. Suddenly the wings seemed to explode in time with the energy's explosion out of the room before creating a worrying silence as Castiel's body slumped against the chair in exhaustion.

Sam stood up quickly, his face a picture of worry and confusion as he saw the lifeless figure that sat awkwardly on the wooden chair. His right arm had escaped from the bonds, dangling towards the floor like a broken twig.

'Castiel?'

No response.

'Cas?'

Suddenly, a groan escaped Castiel's lips as his head seemed to slowly turn straight, his body moving as upright as he could despite the ropes around his arm and legs.

'Hey, maybe its best you don't move' Sam held out his hands in protest as if to stop Castiel, but realised that they wasn't really anything he could do to help. 'What happened to you Cas?'

Castiel coughed, his lips cracked and bleeding as he stared deep into Sam's chestnut eyes: 'I'm no longer….an angel now…Sam. It's gone…'

'What's gone?'

'My soul…my angelic soul has…ripped from me…I have no rights to heaven…' Castiel closed his eyes, a single tear falling from his crimson soaked face. 'I'm most certainly…a demon…'

Sam moved towards Castiel noticing that his flesh continued to be hot, however it was significantly cooler than it was before. He didn't care. Sam wrapped his right arm around Castiel's juddering shoulders in comfort, allowing his head to lean against Castiel's trying to soothe the once-angel's shuddering sobs. Castiel's right hand rose up, taking hold of Sam's hand, and squeezed it tightly, before breaking down into an uncontrollable unleashing of upset and pain, tears of redness soaking deep into Sam's shirt.

'It's okay Cas…' Sam said, trying to remain calm for Castiel's benefit. 'Dean will be back soon…and then we will take care of you…'

'You promise?'

'Yeah Cas…don't you worry about a thing…'

As Castiel closed his eyes tight, Sam saw a single vein pronounced on Castiel's neck, the newly transformed demon blood pumping through the vein almost in rage. Sam's tongue subconsciously ran over his lips, as his stomach began to cry out……for the sweet taste of demon blood.


	4. Chapter 4

**Author's Note: Just a Short Chapter this time for update…**

'So that's two cheeseburgers and a small soda?'

Dean only nodded as he sat in one of the booths of the diner, not even looking at the waitress that was taking his order; instead, he held his head deep into his hands and stared into the cushioned material of the seat opposite him. With a deep sigh, Dean began rubbing his forehead in anxiety, trying to remove images of a demonic Cas from his mind. He closed his eyes, allowing his hands to completely cover his face, as he tried to sink into some sort of darkened daydream.

'You can't save him Dean…'

A sudden cold wind wrapped itself around Dean's shoulders as a voice, smug, emotionless and instantly recognisable startled Dean back to reality.

'Zach…' Dean exhaled heavily, his tone dropping into a whisper. 'Son of a bitch…'

Opening his eyes, he saw the corrupted angel in the seat opposite him, a twisted grin on his face as his hands were clasped together on the table.

'I'm not in the mood for your games…I'm really not.'

'Dean! Please, give me some credit…' Zachariah maintained the sadistic expression that corroded his face, staring at Dean with almost extreme mockery. 'I'm here to help of course.'

'Help? Do you know the meaning of the word?'

'Dean, please…Castiel was an angel. He was one of my brothers and…I am deeply saddened about what has happened…and well…I wish to help out.'

Dean raised his head from his hands, fixing Zachariah with confusion: '…what do you mean _was _an angel?'

Zachariah grinned, causing Dean's face to redden in anger. 'Castiel is a fully fledged demon now. Didn't you know?' He began to giggle under his breath. 'Sam knows…he saw the beautiful transformation unfold in front of him.'

'Shit…'

'Oh don't worry…Sam is absolutely fine…considering…'

Dean's eyebrows began to knit in added uncertainty, the constant urge to meet his fists with the angel's face becoming more appealing to act upon. 'What the hell does that mean…_considering?'_

'Oh I just mean the hunger that is eating inside your brother's soul…' Zachariah flashed Dean a menacing smile. '…for Castiel's blood, you understand.'

Dean scoffed, a disbelieving expression sweeping across his face: '…Sam would never go back to that…' His tone began to get louder in anger. '…Never!'

Zachariah held up his hands as if he had been caught out, however his mouth still continued to smile threateningly towards Dean, as if telling this truth had made his day.

'Whatever you say Dean…you know your brother better than anyone of course…tell me, what did you see in 2014 involving your little Sammy?'

'Just shut your mouth…'

Dean suddenly got up from his chair as he proceeded to walk out of the diner straight for his Impala…and straight back to the hotel.

'Dean…' Zachariah stated, before Dean exited the diner. 'Remember this is only to help…'

'Fuck you.' Dean whispered under his breath, grabbing hold of the door handle in rage, as he stormed his way towards the Impala.

Zachariah could only snigger under his breath until suddenly the waitress appeared, clutching hold of a silver tray on which the cheeseburgers and the soda were laying on.

'My friend had to go unexpectedly…' he said grabbing hold of the food almost in frenzy. 'But I'll be more than happy to eat it on his behalf…paying for it of course.'

The waitress simply shrugged, walking away with the now empty tray in her right hand as Zachariah stared out of the window, taking a bite out of the juicy burger as he saw Dean speed away in anger back towards the hotel.


End file.
